It took only a day or two for a geniuses hacker, Pod2G, after the official release of iOS 4.1 to found out a bootrom exploit in the final iOS 4 version. This news was confirmed by one of Dev-Team members, MuscleNerd via his recent tweet:

The man still working to get the job done for the iOS 4.1 jailbreak to be released. We need to wait for the exploit based bootrom to be released to the public and then jailbreak our iPhone running on iOS 4.1 and to unlock it. As the tweet says above: keep away from 4.1 Firmware update!